FR2662022A1 - Cathode-ray tube and method for its manufacture - Google Patents

Abstract

The invention relates to a cathode-ray tube and a method for its manufacture. …<??>The tube (1) includes, over at least part of the outer surface of its front plate (2), a layer consisting of at least one coloured transparent electrically conducting region (8) formed by at least one organic dye, at least one electrically conducting metal oxide chosen from the group including tin oxide, indium oxide and antimony oxide; and silica consisting mainly of a silica gel, and of at least one antireflection protective region (9) consisting mainly of silica. …<??>Application especially to cathode-ray tubes having stable optical, antistatic and antireflection properties and high contrast. … …

Description

The present invention relates to a cathode ray tube having

extensive and stable optical properties, a

high contrast, antistatic characteristics allow

both the efficient elimination of the electricity produced by static induction on the panel, and the mechanical durability

high chemical and chemical levels, as well as a process for manufacturing

quer such a cathode ray tube.

As a means for imparting to a ca-

thodic (a) an ability to rapidly transfer electricity

tricity produced by static induction caused by closing or opening of the switch, to ground, i.e. an antistatic characteristic, and (b) high image contrast, the authors at the basis of the present invention have previously provided a method for forming a colored transparent electroconductive film on the faceplate of a cathode ray tube (application

Japanese Patent No. 1-145325) That is, the inventions

authors have proposed a method for forming a colored transparent electroconductive film by means of the deposition,

on the outer surface of the front plate of a ca-

thodic, an alcoholic solution containing one or more

sieurs organic dyes, at least one electrically conductive metal oxide chosen from tin oxide (Sn O 2), indium oxide (In 203) and antimony oxide (Sb 2 03), and a silicate ethyl, and heating and drying the surface to a temperature of about 100 * -2000 C.

In the process indicated above, one prepares

rait the alcoholic solution by first preparing a solution consisting of at least one metal oxide chosen from Sn O 2, In 203 and Sb 2 03, ethyl silicate capable of

form a silica sol when subjected to hydro-

lysis, followed by condensation by dehydration, a solution

mixed ration consisting of alcohols, ketones or the like, water and an acid catalyst, then adding to this solution at least one organic dye capable of providing the desired optical properties and chosen from azo dyes, dyes anthraquinone-based and the like; and the deposit of the alcoholic solution was a deposit by

rotation, dip deposition or spray deposition-

tion.

However, the technique indicated above can be

Knows the following problems That is, the colored transparent electroconductive film can achieve the desired light absorption when it contains one or more organic dyes in an amount as low as 1% by weight or less, and can provide high image contrast; however, early color degradation tends to occur in the film when exposed to water, acid, alkali, organic solvent or the like. Color degradation occurs in the film over a period of time time of about an hour, especially at high temperatures, for example when placed in boiling water Since it is expected that electrical apparatus using said film can be subjected to high temperatures and to high humidity during storage, transport by sea, etc., it has been found necessary to improve water resistance and chemical resistance

of the film.

Further, there has been the problem that when a solution is deposited on the front plate to form a colored transparent electrically conductive film and then or simultaneously deposited on the thus coated front plate, a solution to form an anti-reflective surface protective layer consisting mainly of an alcoholic solution containing ethyl silicate, the dye or other components present in the colored transparent electroconductive film dissolve and spread in the anti-reflective surface protective layer as the

surface of said film is unstable and active.

Since the solution for forming an anti-reflective surface protective layer contains a large amount of alcohol, water, etc. and has a low viscosity, it tends to dissolve the dye, etc. present in the transparent electrically conductive film

colored When such a dissolution occurs, the colo-

rant is removed when the surface of the tube is cleaned.

thodic with a solvent, and it follows that the tube ca-

thodic has altered optical properties.

In addition, the organic dyes commonly used

do not exhibit chemical durability and

sufficient optics and need to be improved.

An aim of the present invention is to solve the problems of the prior art mentioned above and

to provide a cathode ray tube having op-

extensive and stable ticks, high contrast, an ability to efficiently remove electricity generated by static inductance on the faceplate, and high mechanical and chemical durabilities, and to provide a process

to make such a cathode ray tube.

Another object of the present invention is to re-

to overcome the problems of the prior art and to provide a cathode ray tube capable of selectively absorbing two intermediate colors, magenta and cyan, so as to obtain improved contrast, high purity of colors and brighter colors, and

provide a method for making such a cathode ray tube.

In accordance with the present invention it is provided

(1) a cathode ray tube, of which at least part of the over-

outer face of the front plate is covered with a layer, characterized in that this layer comprises

(A) at least one electrically conductive region trans-

colored parent formed by (a) at least one organic dye

nic, (b) at least one electrically conductive metal oxide selected from the group including tin oxide, oxide

indium and antimony oxide, (c) silica, which is

killed primarily by silica gel, and (B) at least one anti-reflective protective region consisting primarily of silica; and

(2) a process for making a cathode ray tube, characterized by

ized in that it comprises the steps of: (A) depositing on at least part of the outer surface of the front plate of a cathode ray tube, a

alcoholic solution containing (a) at least one gold dye

ganic, (b) at least one electrically conductive metal oxide selected from the group consisting of tin oxide, indium oxide and antimony oxide, (c) an alkyl silicate, (d) of water and (e) an acid catalyst, (B) depositing an alcoholic solution containing an alkyl silicate on the surface of the faceplate, which was covered in step (A), and (C) drying by heating the undried, multi-layered faceplate obtained in step (B); and

(3) a process for making a cathode ray tube, characterized by

ized in that it comprises the steps of: (A) depositing on at least part of the outer surface of the front plate of a cathode ray tube, a

alcoholic solution containing (a) at least one gold dye

ganic, (b) at least one electrically conductive metal oxide selected from the group consisting of tin oxide, indium oxide and antimony oxide, (c) an alkyl silicate, (d) of water and (e) an acid catalyst, (B) applying a vapor to the surface of the front plate, which was covered in step (A), (C) depositing an alcoholic solution containing a silicate of alkyl on the surface of the front plate, which has been covered and to which steam has been applied and was obtained in step (B), and (D) dry by heating the front plate to

multiple layers, not dried, obtained in step (C).

Other features and advantages of the in-

vention will emerge from the description given below

taken with reference to the accompanying drawings.

Figure 1 shows a front view, partial-

partly broken away, showing the overall arrangement of one embodiment of the cathode ray tube according to the present

invention In Figure 1, the reference numeral 1

sign the cathode ray tube, the reference numeral 2 a faceplate, the reference numeral 3 a funnel, the

reference number 4 a sintered glass, the reference number

number 5 a fluorescent substance, the reference number

6 an aluminum film deposited, the reference number

7 is a shadow mask, the reference numeral 8 is colored transparent electrically conductive regions and the

reference numeral 9 of the anti-radiation protective regions

flounders. Fig. 2 is an illustration showing the emission spectra of fluorescent substances in the colors red, green and blue and the selective absorption characteristics of electroconductive regions

colored transparencies In figure 2, the number of

10 denotes the emission spectra of fluorescent substances, B, G and R denote respectively blue, glass and red, the reference numeral 11 denotes the selective absorption characteristics of regions

transparent colored electroconductive, (a) relate to

both to Example 2, (b) relating to Examples 1, 4, 5 and 6 and to Comparative Example 1 and (c) relating to

example 3.

Figure 3 represents the transmit-

initial spectral tance of transparent electroconductive regions colored in the examples and in the example

comparative.

Figure 4 is a graph showing the variations

tions, over time, of the spec-

transparent colored electrically conductive regions

rees in the examples and in the comparative example.

The cathode ray tube according to the present invention

tion has, over at least part of the outer surface

top of its front plate, a layer comprising at least

a colored transparent electroconductive region (desi-

hereinafter referred to as the CTE region) and at least one anti-reflective protective region (hereinafter referred to as the

NGP region term).

The CTE region consists of (a) at least one organic dye, (b) by at least one electrically conductive metal oxide chosen from the group comprising tin oxide, indium oxide and antimony oxide , and (c) of

silica consisting mainly of silica gel.

The CTE region can be in the form of a film, a

disc or ring.

The type of organic dye is not particularly limited. It is preferably selected from acid dyes, cationic dyes, reactive dyes, direct dyes and disperse dyes, these dyes exhibiting high light stability. and high chemical resistance Specific examples of such a dye include sodium fluorescein, rhodamine, oil blue, oil violet, acid rhodamine B, alizarin direct blue

AGG, acid light yellow 2 G, acid red 3 bl, supra-

sirius orange GGL and E-SNA reagent yellow Can be used alone, or in combination of two or more

large number.

To obtain improved contrast, it is effective

owing to (a) choose from among the organic dyes indicated above a combination of different dyes capable of selectively and simultaneously absorbing a magenta color having a wavelength in the vicinity of 560-580 nm and a cyan color having a length of 480-500 nm, these two wavelengths being emitted by fluorescent substances deposited on the inner surface of the front plate, and (b) using said combination of different dyes in a solution

to form the CTE region described later.

The different dyes used in combination can be present on the outer surface of the front plate of the cathode ray tube as two or

of a greater number of layers, each of which is a re-

gion CTE in the form of a film containing an organic dye.

particular nick possessing a characteristic

of particular absorption, or otherwise in the form of a re-

gion CTE in the form of a film containing at least two co-

different organic lorants with different characteristics

different absorption ticks, or alternatively in the form of two layers, one of which is a film-shaped CTE region containing an organic dye and the other of which is a film-shaped CTE region containing two or

several other organic dyes.

By giving the film-shaped CTE region a selective absorption characteristic for magenta and cyan color, a light-colored tint on the longer wavelength side is deeper than the color tint that one obtains with the conventional technique with the absorption of the magenta color, which makes it possible to obtain a brilliant image, and a blue-green color which is suppressed by the absorption of the cyan color, which makes it possible to get distinctly

one color blue and one color green.

The use of the organic dyes mentioned above also makes it possible to obtain a cathode ray tube exhibiting precise absorption characteristics, a

excellent lightfastness and excellent stabilization

chemical ity.

The amount of organic dye (s) used

sés in the CTE region is not subject to any particular limitation.It is generally equal to 1% by weight or less of the amount of the solution used to form the

CTE region which will be described later.

The metal oxide used in the CTE region is at least one electrically conductive metal oxide selected from the group consisting of tin oxide, indium oxide and

antimony oxide.

The shape and size of the metal oxide are not subject to any particular limitation. However,

the metal oxide generally has diamonds

meters not greater than the wavelength of visible light, preferably not greater than 100 nm and so

preferentially not greater than 50 nm and in a manner

more preferential core not greater than 10 nm.

The amount of metal oxide used in the CTE region has no particular limitation. However, the metal oxide is generally used in an amount such that the resulting cathode ray tube has resistance.

equal to 105-101 l D / cm 2.

The form of the silica consisting mainly of silica gel and used in the CTE region is not subject to any particular limitation. However, it is

preferable that it is in the form of fines by-

ticules, of a uniform layer or of a mixture of these two types.

The cathode ray tube according to the present invention

tion can be manufactured by either of the following two processes:

(1) a process for manufacturing a cathode ray tube, characterized

ized in that it comprises the steps of: (A) covering at least a part of the outer surface of the front plate of a cathode ray tube with a

alcoholic solution containing (a) at least one gold dye

ganic, (b) at least one electrically conductive metal oxide selected from the group consisting of tin oxide, indium oxide and antimony oxide, (c) an alkyl silicate, (d) of water and (e) an acid catalyst, (B) depositing an alcoholic solution containing an alkyl silicate on the surface, which has been coated, of the faceplate obtained in step (A), and ( C) drying by heating the undried multi-layered faceplate obtained in step (B); and

(2) a process for making a cathode ray tube, characterized by

ized in that it comprises the steps of: (A) covering at least a part of the outer surface of the front plate of a cathode ray tube with a

alcoholic solution containing (a) at least one gold dye

ganic, (b) at least one electrically conductive metal oxide selected from the group consisting of tin oxide, indium oxide and antimony oxide, (c) an alkyl silicate, (d) of water and (e) an acid catalyst, (B) applying a vapor to the surface of the front plate, which was covered in step (A), (C) depositing, by means of a deposition by spraying, spin coating or dip coating, an alcoholic solution containing an alkyl silicate on the faceplate surface, which has been coated and to which steam has been applied and which has been obtained during step (B), and (D) dry by heating the front plate to

multiple layers, not dried, obtained in step (C).

We will first describe the process (1).

In method (1), the solution used for the formation of the CTE region is an alcoholic solution containing (a) at least one organic dye, (b) at least one electrically conductive metal oxide selected from the group including the oxide of tin, indium oxide and antimony oxide, (c) an alkyl silicate, (d) water and (e)

an acid catalyst.

The types of organic dyes (a) and metal oxides (b) have been described above. Specific examples of the alkyl silicate

are methyl silicate, ethyl silicate, sili-

n-propyl cate, isopropyl silicate, silicate of

n-butyl, isobutyl silicate, sec-

butyl, and tert-butyl silicate Among these substances, methyl silicate and ethyl silicate are preferable, and ethyl silicate is even more preferable. The acid catalyst (e) can be any acid as long as it can produce the hydronium ion when dissolved in water. Specific examples of the acid catalyst (e) are hydrochloric acid, acid

nitric, acetic acid and sulfuric acid.

Alcohol can be any alcohol in the

measure o it is compatible with water Specific examples

fics of alcohol are methanol, ethanol, propa-

nol, isopropanol, tert-butyl alcohol, ally- alcohol

lique, ethylene glycol and glycerol.

The solution for forming the CTE region may further include small amounts of ketone, etc. The amount of organic dyes (a) used

in the solution used to form the CTE region is not

setting no particular limitation, but is generally not

ral not more than 1% by weight.

The amount of metal oxides (b) used

in the solution used to form the CTE region is not

setting no particular limitation, but is used

generally so that the cathode-ray tube

dique obtained has a resistance equal to 102-1011 a / cm 2.

The solution for the formation of the CTE region it

can be obtained by mixing the specified components

ques previously and their agitation so as to obtain

a uniform solution.

The method for depositing the solution for forming the CTE region on the faceplate of a cathode-ray tube is not subject to any particular limitation, but generally a sputtering, dip-coating or spray-coating is used. rotation The deposit by

immersion or deposition by rotation makes it possible to obtain a

film-shaped CTE gion, and spray deposition

It is possible to form CTE regions in the form of overlapping discs or rings Some of the CTE regions in the form of discs or rings have a diameter of µm or less Others have a diameter of about 20 µm or 50 µm or more This deposit provides a front plate, the surface of which is covered, and which comprises a front plate on which is deposited the solution used to form

the CTE region.

The solution used for the formation of the re-

gion NGP is an alcoholic solution containing a silicate

alkyl, water and an acid catalyst.

The types of alkyl silicate, alcohol and

acid catalyst have been described previously.

The amount of alcohol used in the solution

used to form the NGP region is not subject to any limitation.

particular ration, but is generally equal to 40-95% by weight The composition of the alcohol is not subject to any

particular limitation, but preferably comprises 39-

% ethanol and 1-10% by weight of isopropanol The amount

tity of the acid catalyst and water in the solution

to form the NGP region is not subject to any limitation.

tion, but is generally 2-50% by weight. The amount of the alkyl silicate in the solution

used to form the NGP region is not subject to any limitation.

particular ration, but is equal to 0.3-5% by weight under

the form of silica formed by decomposition.

The solution used to form the NGP region can

be obtained by mixing the components indicated above

and stirring them to obtain a uniform solution.

The process for depositing the solution is

to form the NGP region on the surface of the front plate which is covered and is constituted by a front plate on which is deposited the solution serving to form

the CTE region is not subject to any limitation by-

t particular, but generally a coating is used.

Preferably, the solution used to form the NGP region is deposited so as to cover the whole of the part of the solution used to form the CTE region and deposited on the plate. before Dip coating or spin coating allows

to obtain a film-shaped NGP-region, and the coating

Spraying provides NGP regions in the form of overlapping discs or rings. This deposition provides an undried, multi-layered front plate comprising a front plate, the solution being used for

form the CTE region and deposited on this plate and the so-

lution used to form the NGP region and deposited over

the previous one.

The heating drying conditions of the undried multi-layered front plate comprising the front plate, the solution for forming the CTE region and deposited on the plate and the solution for forming the NGP region and coated on the previous solution are not subject to no particular limitation, but consist

preferably by heating at 80 ° -2500 C for 5-120 mi-

nutes It is thus possible to obtain a cathode-ray tube conforming to

the present invention.

The CTE regions formed as indicated above

ment include organic dyes and a stable reaction product obtained from an alkyl silicate and therefore provide colors within a wide range, simply by choosing organic dyes with desired optical characteristics

and the appropriate determination of their quantities.

CTE gions further comprise at least one electrically conductive metal oxide chosen from Sn O 2, In 203 and Sb 2 03 and by

therefore may exhibit an anti-static characteristic.

stable and sufficient tick.

In the cathode ray tube conforming to this

invention, the CTE regions are covered with si-

lice consisting mainly of silica gel, and by

therefore provide chemical and mechanical durability.

improved In addition, silica, which has an

refractive index (equal to about 1.4) less than those of Sn O 2, In 203 and Sb 2 03 and used as a substance

electrically conductive, has an anti-reflective effect and may contribute

buer to effectively control the op-

ticks That is, the CTE regions themselves, which

have a refractive index equal to 1.5-1.52, does not

do not reduce the refractive index of the front plate (1.52) and provide a shiny appearance; however, the use of silica to cover the CTE region allows

reduce the refractive index of the front plate.

The process (2) will be described below.

In method (2), the solution used for the formation of the CTE region is an alcoholic solution containing (a) at least one organic dye, (b) at least one electrically conductive metal oxide selected from the group including the oxide of tin, indium oxide and antimony oxide, (c) an alkyl silicate, (d) water, and (e)

an acid catalyst.

The types and quantities of the components used

in the solution used to form the CTE region were de-

previously written.

The solution used to form the CTE region can be obtained by mixing the components indicated above and stirring them so as to obtain a

uniform solution.

The method of depositing the solution for the forma-

tion of the CTE region is not subject to any limitation

t particular, but a deposition by spraying is generally used.

sation, immersion deposition or rotational deposition This deposition makes it possible to obtain a front plate the surface of which is covered and which comprises a front plate on which

the solution used to form the CTE region is deposited.

Then steam is applied to the front plate

whose surface is covered.

The temperature of the steam is not lower than 30 ° C and is generally equal to 30 -1000 C. The reason for applying a steam to the surface of the faceplate whose surface is covered, after depositing the solution used to form the CTE region

on the surface of the front plate, is to promote the re-

subsequent hydrolysis action of the alkyl silicate and the subsequent dehydration condensation reaction to

forming a resistant film of silica (Si O 2).

Si (OR) 4 + 4 H 20 -> Si (OH) 4 + 4 ROH (1) 2 Si (OH) 4 -> 2 Si O 2 + 4 H 20 (2)

R being an alkyl.

As soon as the solution used to form the CTE region has been deposited on the outer surface of the plate

* before, the reactions indicated above are not understood.

pletes at the surface of the deposited solution Furthermore, the solution used to form the NGP region and which

must be deposited next, has a low viscosity.

Therefore, if the solution used to form the NGP region comes into contact with the solution used to form the NGP region.

CTE region and for which the reactions indicated above are not sufficiently produced, a

dissolving the dyes, etc. present in the solution for forming the CTE region, in the solution for forming the NGP region However, the de-

the solution used to form the NGP region, the reaction

subsequent condensation by dehydration and the

resulting formation of a stable Si O 2 film allows

tries to prevent the leakage of dyes; etc and allows to obtain a combination of CTE regions and NGP regions, which has high mechanical and chemical resistance

and which is optically stable.

In this regard, the reason why the temperature

ture of steam applied to the deposited solution and used

for the formation of the CTE region is equal to prefe-

at 300-1000 C, and that the value of 30 C represents the

lowest temperature at which the reactions induce

previously stated can be monitored over the course of a year, and at temperatures above 100, the fluidity of the solution for the formation of the NGP region

is greatly reduced and the degree of spreading of the sol-

lution is reduced, which in some cases results in insufficient coverage by the solution and obtaining

rough-surfaced film.

Therefore, the application of a steam results in a faceplate whose surface is covered and to which the steam has been applied and in which the alkyl silicate in the deposited solution serving to

forming the CTE region was hydrolyzed.

The constituents used in the solution serve

before forming the NGP region and the separation process of

the solution have been described previously.

The process for depositing the solution is

before forming the NGP region on the described front plate

previously, the surface of which has been covered and at the-

which steam has been applied, is not subjected to

particular limitation, but a deposition by pul-

verization, immersion deposition or rotary deposition

It is preferable that the solution used to form the NGP region is deposited so as to cover as completely as possible the deposited solution used to form the NGP region.

the CTE region Immersion deposition or rotational deposition

The result is an NGP region in the form of a film.

Spray deposition leads to the formation of re-

NGP gions in the form of overlapping discs or rings.

Therefore, a layered faceplate can be obtained

multiple undried, comprising a faceplate, the solution

tion used to form the CTE region and deposited on this

plate and the solution used to form the NGP region deposited

based on the previous solution, the alkyl silicate located in the solution used to form the CTE region having been

hydrolyzed by the application of steam.

The heating drying conditions of the undried multi-layered faceplate are not subject to particular limitation, but correspond to

preferably at the application of a temperature of 80 -

2500 C for 5-120 minutes.

Therefore, a cathode ray tube can be obtained.

dique according to the present invention.

The cathode ray tube and the process for its manufacture

tion in accordance with the present invention will be described

here specifically by way of example.

Example 1

FIG. 1 is a sectional view showing the overall arrangement of an example of the cathode ray tube according to the present invention In FIG. 1, the cathode ray tube 1 comprising a front plate 2, a region

electrically conductive transparent colored 8 (hereinafter designated

after under the term CTE region) arranged on the surface

outside of the front plate 2, a protective region an-

leglets 9 (hereinafter referred to as the NGP region) which covers the CTE region 8, fluorescent substances arranged on the inner surface of the front plate 2,

a deposited aluminum film 6, formed on the sub-

fluorescent stances 5, a perforated mask 7, a funnel 3 fused to the front plate 2 and comprising a sintered glass, etc. The procedure for forming the film-shaped CTE region 8 and the NGP film-shaped region 9 will be described below. First, the outer surface of the front plate 2 is cleaned using an abrasive 1, for example. cerium oxide (Ce O 2) l and with an alkaline cleaning agent (a product marketed by

Henkel-Hakusuisha) Then we deposit evenly on the sur-

external face a mixed solution obtained by adding a

organic dye to a solution consisting of a sub-

electrically conductive stance (Sn O 2 + Sb 2 03), silicate

ethyl, a mixture of solvents (ethanol, IPA, other al-

cools and ketones), water and an acid catalyst, using

reading a rotary coating device to form a film-shaped CTE region 8 To make a 35.6 cm type cathode ray tube, the amount of the deposited solution is 10 ml; the rotation of the rotary coating device was equal to 100 rpm, and the coating time was equal to 1 minute Then, on the film-shaped CTE region 8, a solution for forming the film was spray coated. NGP region and having a composition shown in Table 1 so as to

form a film-shaped NGP region 9 When de-

spray pot, a commercially available pneumatic spray gun was used to spray a substance of low viscosity (amount of the solution

deposited: 20 ml, duration of deposit: about 30 seconds) In-

then drying is carried out by heating at 150 ° C. for

30 minutes, which made it possible to obtain a front plate

with a resistant film-shaped CTE region 8 and

a resistant NGP region 9.

The subsequent procedure was the same as that customarily used in the art, which made it possible to complete the manufacture of a cathode ray tube.

Examples 2-4

A cathode ray tube of the same size was prepared.

as in Example 1, except that the type

of dye used, as shown in Table 1.

Example 5

A cathode ray tube of the same size was prepared.

as in Example 1, except that the re-

gion CTE by spray deposition.

Example 6

A cathode ray tube of the same size was prepared.

only in Example 5, except that successively

vement the CTE region and the NGP region.

Comparative example 1

A cathode ray tube of the prior art was prepared.

laughing having the same CTE region as in Example 1, but not comprising any NGP region, as described in

present invention.

The cathode ray tubes obtained in Examples 1-6 and in Comparative Example 1 were subjected to the tests.

following.

(1) Color tint

The measurement was performed using the spec-

Hitachi V-3200 trophotometer manufactured by the so-called company

HITACHI LIMITED.

(2) Gloss value The measurement is carried out in accordance with the standard

Japanese JIS Z 8741.

(3) Surface resistance The measurement is carried out using the high resistance tester TR-3 manufactured by the company called Tokyo Denshi, Co, Ltd. (4) Penetration resistance of a tip The measurement is carried out in accordance with the standard

JIS K 5401.

(5) Chemical resistance It is expressed by the duration of reduction of

half the color intensity of a film, when

that the latter is immersed in boiling water.

Table 1, reproduced below, shows the re-

results of Examples 1-6 and Comparative Example 1, i.e. the composition and deposition method of the solution used for the formation of the CTE region, the composition and the deposition method of the solution used

for the formation of the NGP region, the conditions of

chage by heating and the properties (color tint)

their, gloss value, surface resistance, re-

point penetration resistance, chemical resistance)

of the resulting multi-layered faceplate.

Table 1 shows that the cathode ray tubes of

examples 1-6 provided a gloss value equal to 70-

%, which was about 25-30% lower than

of Example 1, and they showed im-

load-bearing from the point of view of the resistance of the penetration

tion of a tip and chemical resistance When each of the tubes of Examples 1-6 was mounted in a

television to examine the picture, one could very easy-

to observe the latter because of the lower coef-

external light reflection efficiency (the brightness value is reduced by 25-30%) Each of the tubes of Examples 1-6 had a surface resistance equal to 107 Q / o and, each of these tubes, mounted in an apparatus

television to measure the decay time

surface potential at the time of connection or

of the judgment, exhibited a sa-

satisfactory.

Further, when the tubes of Examples 1-6 were mounted in a television set, the parts

unnecessary light emitted by fluorescent substances

red, green and blue centes were eliminated by the specific absorption of light achieved by the CTE region, which provided improved contrast, improved color purities and a sharp image In Figure 2 the emission spectra are shown. 10 red, green and blue fluorescent substances and the selective light absorption characteristic 11 of the CTE region for Examples 1-6 It can be seen in Figure 2 that the intermediate colors (shown as oblique lines) emission spectra 10 of substances

fluorescent cells are selectively eliminated by the

characteristic 11 of selective absorption of light from the

CTE region, which provided ac-

harsh, deeper colors and increased contrast.

In each of Examples 1-6, a

sole colorant, but it is possible to use in combination

its different colorings according to the customer's taste,

etc. and considering the durability of each dye.

Table 1

(Composition:% by weight

Example

E x e m p 1 e comparative

1 2 3 4 5 6

Fluorescein with sodium O 2 41- Rhodamine dye 0.2 O> 2 0.2 O "2 organic" organic Oil blue 0.2 e @ 4 4, Oil violet -_ 02 2 Electrically conductive substances 0 'e 0 -0 (Sn O 2+ Sb 203) CQ Ethyl silicate 1.3 1.3 1.3 1.3 2.5 2.5 1.3 eo Solvent, water and catalyst 975 975 975 97.5 96.5 96.5 97.5 97 o 5 97 t 5 97 P 5 EI <3 Deposition process 8 t rotation rotation rotation spraying spraying rotation Ethyl silicate 2.5 2; 5 2.5 2.5 2.5 2.5) continued Ni p Table 1 (continued) s -i o.

4- '' O)

os o) -D 0 S s tu O oi 1 OO 0 r 54 4 J 4 'O OR à 01 Alcohol Catalyst and water 40 40 40 40 40 40 Low constituents 2 5 2.5 2.5 2.5 2, 5 2.5 quantities Deposition process

pulverized

tion

pulverized

ion

pulverized

tion

pulverized

tion

pulverized

Spraying (juice after removing the electroconductive solution) Drying conditions by heating 150 C x 30 minutes

Color tint (transmitted-

Color tet (transmitted Fig 2 Fig 2 Fig 2 Fig 2 Fig 2 Fig 2 Fig 2 Sion etaorption) b a c b b b b Gloss value 70 70 10

75 75 75 70 '70 O

(JIS Z 8741) (%)

Surface resistance 7 7 7 7 (Q /) 10 7 10 10 10 107 107 107 d Resistance t penetration pone tip

(JIS K 5401) 6 H 6 H 6 H 6 H 9 H 9 H HB

(JIS K 5401)

o * Qchemical resistance 5 l h <5 h <5 h <5 h <5 h <5 h <0 5 h> * At the time o the color of a boiling. film weakens to half of its value while film is submerged in water t) K) OG t O t O

Example 7

Figure 1 is a sectional view showing

the overall arrangement of a cathode ray tube manufactured in accordance

ment to the method according to the present invention In Figure 1, a cathode ray tube 1 comprises a front plate 2, a CTE region 8 disposed on the outer surface of the

front plate 2, an NGP region (silica consisting mainly of

also by a silica gel) 9 covering the CTE region 8,

fluorescent substances 5 provided on the interior surface

of the front plate 2, an aluminum foil de-

laid 6 formed on the fluorescent substances 5, the perforated mask 7, a funnel 3 fused to the front plate 2 and comprising a sintered glass, etc. Hereinafter, the method for forming the CTE region 8 and the NGP region 9 will be described.

the outer surface of the front plate 2 of a cathode-ray tube

dique 1 finished using an abrasive (for example

cerium oxide) and an alkaline cleaning agent manufactured

qué by the company called Henkel-Hakusuisha Then, we de-

uniformly laying, on the outer surface, a mixed solution obtained by adding an organic dye to a solution consisting of electrically conductive substances

(Sn O 2 + Sb 2 03), ethyl silicate, a mixed solvent pos-

seducing the same composition as in Example 1, water and an acid catalyst, using a rotary coating device to form a CTE 8 region In this case, the amount of the mixed solution deposited was equal to

ml, the rotational speed of the coating device ro-

tative was equal to 100 rpm and the coating time was

equal to 1 minute, which made it possible to obtain a cathodic tube

35.6 cm type disc Then, the obtained cathode ray tube was introduced into an oven so as to preheat the surface of the front plate to about 500 ° C; in this state, steam was introduced into the oven to apply

this vapor on the surface of the front plate for approx.

ron 5 minutes Then, we deposited by spraying, on

the surface of the faceplate, a solution used to form

sea the NGP region and having the following composition Ethyl silicate 2.5% by weight Ethanol 55% by weight HNO 3 and water 40% by weight Additives 2.5% by weight

The tube was introduced into an oven to make a se-

heat by heating at 1600 C for 30 minutes to obtain

a cathode ray tube having a CTE region 8 having a capacity

selective light absorption capacity and a region

NGP 9 (silica consisting mainly of silica gel).

The tube thus obtained had a high resistance.

perfiary equal to 1 x 108 Q / U and a gloss value equal to 80%, measured in accordance with the Japanese standard JIS Z 8741, and in this tube no elimination was observed

dye contributing to the selective absorption of light

under the effect of wiping the surface of the panel and a degradation of the color was obtained under the effect

external light (ultraviolet radiation in parti-

culier) lower than in the tube of the prior art.

Thus, it was possible to obtain a cathode ray tube exhibiting excellent properties such as, for example, a contrast.

high and the absence of glare.

Example 8

According to the procedure of Example 7, a CTE region was formed on the outer surface of the front plate of a cathode ray tube. Then the tube was introduced into an oven; the front plate was preheated to 50 C, then

it was exposed to steam and then deposited by pul-

verifying the same solution used to form the NGP region as that used in Example 7; finally, we dried by

heating the tube to 1600 C for 30 minutes.

The resulting multi-layered faceplate having the same high quality as in the case of

example 7.

Example 9

The faceplate of a cathode-ray tube was subjected to the same treatment as in Example 7, whereupon a solution to form the CTE region was spray coated onto the surface of the faceplate. and of a type similar to that of Example 7 Following the procedure being the same as in Example 7, a cathode ray tube having a CTE region and a cathode ray tube was prepared.

NGP region.

Also in this case, the resulting multi-layered faceplate had a surface resistance equal to 5 x 108 Q / P and a gloss value equal to

%, measured in accordance with JIS Z 8741, does not pre-

felt no reduction in the amount of the dye and pos-

seduces optical stability.

Comparative Example 2 A CTE region and an NGP region were formed in the same manner as in Example 7, except that the steam exposure operation was not performed. elapsed between the formation of the CTE region and the formation of the NGP region, including preheating,

was 10 minutes.

In the multi-layered faceplate thus obtained, the dye located in the CTE region leaked onto the outer surface of the NGP region and a partial reduction in the amount of dye was observed when the surface of the plate was vigorously wiped. before with ethanol In addition, a test revealed that the degradation of

the color under the effect of solar radiation or ray-

ultraviolet light occurred about twice as fast

as in the samples of Examples 7-9.

Comparative Example 3 Two cathode ray tubes of the same

manner as in Comparative Example 2, except that the in-

time intervals between the formation of the CTE region and the formation of the NGP region were equal to 2 hours and

24 hours.

The tube, for which the 2 hour time interval was used, showed a slight improvement in the reduction of the amount of dye, but this improvement was insufficient. The tube, for which an interval of time of 24 hours, showed no reduction in the amount of dye, but such a time interval is not suitable for a

practical application.

Comparative example 4

A cathode ray tube of the same size was prepared.

denies that in example 7, except that we did not realize

contact with the steam, but a spray has been made

rization at room temperature with humidification by

ultrasound There was a slight improvement in the tube

tion from the point of view of reducing the amount of co-

lorant, but this reduction could not be completely eliminated.

mined.

Example 10

Figure 1 shows a sectional view, partial-

torn away, showing the arrangement of a realistic

sation of the cathode ray tube according to the present invention In FIG. 1, the reference 1 designates a cathode ray tube and the outer frame of the cathode ray tube is constituted by a front plate 2, a funnel 3 having a part forming a neck, and a sintered glass sealant 4. in an airtight manner the front plate 2 and funnel 3 Reference 5

designates fluorescent substances and the reference 6 de-

signs a deposited aluminum film, formed on the fluorescent substances 5 The reference 7 designates a perforated mask, the reference 8 a CTE region formed on the

outer surface of the front plate 2, by means of the

given below, and the reference 9 designates an NGP region formed on the CTE region 8 so as to cover this region. The CTE region 8 was formed by following the steps

indicated below.

First, the outer surface of the front plate 2 of a cathode ray tube 1 as shown was cleaned.

shown in Figure 1, using a predetermined procedure

mined; thereafter, a solution used for the formation of the CTE region and containing organic dyes and having a composition shown in the upper part was deposited by rotary coating on the outer surface.

of Table 2 indicated a little later in the present des-

cription; then drying was carried out by heating at 1500 ° C. for 30 minutes so as to form a CTE 8 region. The constituents of the solution other than the dyes are indicated in Table 3, indicated a little further on

in the present description In this regard, the names of the co-

* The dyestuffs shown in Table 2 are those described in the "Dyes Handbook" 1 (published by Maruzen on June 6, 1959) Each number of C I- in Table 2 denotes an index number of

color described in this book.

Examples 11-12

CTE 8 regions of Examples 11 and 12 were formed in the same manner as in Example 10, except that the solution used to form the CTE region was used for the respective compositions shown in Tables 2 and 3. .

Example 13

We formed a CTE 8 region in the same way

than in Example 10, except that it was used as a solution

tion to form the CTE region, two solutions having the compositions shown in Table 2, to form a

CTE region having a two-layered structure.

Example 14

A CTE 8 region was formed in the same manner as in Example 10, except that the formation was performed.

of the CTE region by means of spray deposition.

Example 15

We formed a CTE 8 region in the same way

than in Example 10 Then was deposited by spraying

A solution having a composition shown in Table 4, over the CTE 8 region to form an NGP 9 region.

Example 16

A cathode ray tube was prepared having the same constitution as the tube of Example 15, except that we have

formed the CTE region using spray deposition.

Comparative Example 5 A CTE region 8 was formed in the same manner as in Example 10, except that the organic dye used in the solution to form the CTE region was only B-acid rhodamine.

For each of the multi-layered faceplates

As previously prepared, properties such as color tint, chemical resistance and optical stability were measured.The results are shown in

the lower part of Table 2.

In Table 2, the color tint indicates the sharpness of an image provided by each front plate to

multiple layers as the disappearance of (a) one color

their unnecessary cyan C between the emission spectra B (blue) and G (green) emitted by fluorescent substances, and (b) an unnecessary magenta color M between the emission spectra G and R (red) (see figure 2 ) is expressed by the curve

of spectral transmittance 1, 2 or 3 of figure 3, obtained

bare with each multi-layered faceplate When measuring chemical stability and heat stability

light, each multi-layered faceplate was immersed

tiples in boiling water (chemical stability) or

well it has been exposed to direct sunlight (resistant to

resistance to light), then the alteration in spectral transmittance was measured by examining the hours (chemical stability) or days (light resistance) when each multilayer front plate exhibited a

20% reduction in transmittance (case II on the fi

figure 4) compared to the initial transmittance (case I in figure 4) or showed a 5% reduction in the

transmittance (case III in figure 4).

Table 2

Rhodamine Acid B

(N C I R-52)

(Composition:% by weight

Example

i 11 1 E 12 13 14 e 1 10 1 il 1 12 1 13 1 14 '0.01 0.01 0.01 (second layer) 0.01 Alizarin blue AGG 005 005 005 O 05005 (NC IB-40 ) (first coat) Acid light yellow 2 G 03

(N C I, Y-17)

Acid red 3 BL

(N C I R-254 K) '

0.02 4 J M Super-orange sirius

-0 ô (N C I; 0-39) 0 03

O 'Q) Q 0.03 0.03

(first coat) Reactive yellow o o (N C I IY-102) 03 0 O Solution constituents other than dyes Deposition process rotation rot Ation rotation rotation w CO spray

1 1 I I

to be continued e r.1 o e c o -I 4 J e o t- o o e s-1 e o- (_ c e a L. e o s- a ro c o o c Oo e <o -i o a * -H 'e

JA Te Tns -

l I Uo 4 e 4 o J UOT 9 s Jo Ainl UOI OJ

ú O 'O ú O' 0

SO 'O 50 O

o O TO O TO O 9 T si e; Pdwo x aldw GX 3 e 4 e 4 e 4 ri (e 4 ns) Z nuelqel Table 2 (continued) Constituents of the covering solution (d 6 pÈt per spray) Conditions of drying by heating e 1-t -ta o. O- Color tint (film transmittance) C x 30 minutes Fig 3 Fig. Fig. Fig 3 Fig. Stability Time up to 2 2 5 3 O 5 5 optical Fig 4 II (h) q 'g Resistance Time up to 6 6 5 5 5 3 5 chemical Fig 4 III (h) Optical resistance Days up to Fig 4 II Days to Fig 4 III wb O to follow Table 2 (continued) Table 4 Table 4 Fig 3 Fig 3 Fig 3

1 1 4

5 1

10 3

50 5

100 10

w (.

Table 3

Electrically conductive substances (Sn O 2 + Sb 2 03) 1% by weight Ethyl silicate 1.3% by weight Solvent, water and catalyst 97.5% by weight

Table 4

Ethyl silicate 2.5% by weight Alcohols 55% by weight Catalyst and water 40% by weight Constituents present in small amounts 2.5% by weight From Table 2, it is evident that this

following.

Regarding color tint, each of the multi-layered faceplates of Examples 10-16 achieves sufficient absorption in the M and C ranges and exhibits excellent optical properties.In contrast, the multi-layered faceplate of the comparative example shows sufficient absorption for the M range, but

does not present any absorption for the C range and consequently

quent provides low color purity for the range

bruises.

Regarding chemical stability and light fastness, each of the multi-layered faceplates of Examples 10-16 exhibited high values, and the faceplates of Examples 15-16 exhibited particularly high values. On the contrary, the faceplate multi-layered front of Comparative Example 5

exhibits somewhat low chemical stability and resistance.

rather weak resistance to light This indicates that the combined use of two or more

organic dyes have a synergistic effect on the stabilization

chemicality and resistance to light and that the presence of the NGP region strongly contributes to improving the

chemical stability of light resistance.

As has been described previously, the process

used to manufacture a cathode-ray tube conforming to the pre-

This invention solves the problems of the prior art and easily achieves a cathode ray tube which has wide and stable optical properties, high image contrast, and zero-dimming characteristic.

reflections and in which there is no electrification

tion of the panel under the effect of static induction.

Further, in this embodiment of the pre-

feels cathode tub, the intermediate colors magenta and cyan of the spectra emitted by the fluorescent substances are absorbed selectively and simultaneously, which allows to obtain an improved contrast of image, purities

improved colors and a sharper image.

Further, according to the present method, the in-

the time interval required between the formation of the colored transparent electroconductive film and the formation of the anti-reflective protective film, which was at least 120 minutes in the prior art, can be reduced to 5 or less, that is to say - say in the ratio equal to approximately

1/20 or less This is an important advantage in the way

connection of the cathode ray tube in large series.

Claims (17)

1 Cathode ray tube, of which at least part of the outer surface of the front plate (2) is covered with a layer, characterized in that this layer comprises (A) at least one transparent colored electroconductive region (8) formed by (a) at least one organic dye, (b) at least one electrically conductive metal oxide selected from the group including tin oxide, indium oxide and antimony oxide, (c) silica consisting mainly of silica gel, and (B) at least one anti-reflective protective region (9) consisting mainly of silica. 2 cathode ray tube according to claim 1, ca- characterized in that the layer constituted by the region electrically conductive transparent colored (8) and by the re- The anti-reflective protective region (9) comprises at least one layer of the colored transparent electrically conductive region (8) and one layer of the anti-reflective protective region (B), and the layer of the anti-reflective protective region (B) is formed on the one or more layers of the conductive region transparent colored (8). 3 cathode ray tube according to claim 1, ca- characterized in that the transpa- colored annuity (8) is a continuous layer and the anti-reflective protective region (9) is formed on this layer, in the form of overlapping discs or rings. 4 cathode ray tube according to claim 2, ca- characterized in that the layer or layers of the electro- colored transparent conductor (8) are in the form of overlapping discs or rings and that the layer of the anti-reflective protective region (9) formed on the preceding layer or layers is a continuous layer. Cathode ray tube according to claim 1, ca- characterized in that the transpa- colored annuity (8) is in the form of discs or overlapping rings and that the protective anti- reflections (9) formed on the electrically conductive region pre- feels in the form of overlapping discs or rings. 6 cathode ray tube according to claim 1, ca- characterized in that the colored transparent electrically conductive region (8) selectively absorbs light having a wavelength in the vicinity of 560- 580 nm and a light having a wavelength located in the vicinity of 480-500 nm. 7 cathode ray tube according to claim 1, ca- characterized in that the silica consisting mainly of silica gel has the form of a film and / or is made up of fine particles. 8 cathode ray tube according to claim 1, ca- characterized in that the electro-metallic oxide (s) conductors have particles of equal diameter or less than 100 nm. 9 Method for making a cathode ray tube, ca- characterized in that it comprises the steps of: (A) depositing on at least part of the outer surface of the front plate (2) of a cathode ray tube (1), an alcoholic solution containing (a) at least an organic dye, (b) at least one electrically conductive metal oxide selected from the group consisting of tin oxide, indium oxide and antimony oxide, (c) an alkyl silicate, (d ) water and (e) an acid catalyst, (B) depositing an alcoholic solution containing an alkyl silicate on the surface of the front plate (2), which was covered in step (A), and (C) drying by heating the front plate (2) to multiple layers, not dried, obtained in step (B). Method according to claim 9, characterized in that the alkyl silicate is ethyl silicate. 11 The method of claim 9, characterized in that the acid catalyst is at least one acid selected from the group comprising hydrochloric acid, acid nitric, acetic acid and sulfuric acid. 12 The method of claim 9, characterized in that the alcohol is a mixture of ethanol and isopropa- nol. 13 The method of claim 9, characterized in that the deposition of the coating is a deposition by spraying, dip coating or spin coating. 14 A method according to claim 9, characterized in that the drying by heating is carried out at 80-250 'C for 5-120 minutes. A method for manufacturing a cathode ray tube, characterized in that it comprises the steps of: (A) depositing on at least a part of the outer surface of the front plate (2) of a cathode ray tube (1), a solution alcoholic containing (a) at least one organic dye, (b) at least one electrically conductive metal oxide selected from the group consisting of tin oxide, indium oxide and antimony oxide, (c) a alkyl silicate, (d) water and (e) an acid catalyst, (B) applying a vapor to the surface of the front plate (2), which was covered in step (A), (C) depositing an alcoholic solution containing an alkyl silicate on the surface of the faceplate (2), which has been covered and to which steam has been applied and was obtained in step (B), and (D) dry by heating the front plate (2) to multiple layers, not dried, obtained in step (C). 16 The method of claim 15, characterized ized in that the steam has a temperature of 30 - 1000 C. 17 The method of claim 15, characterized ized in that the alkyl silicate is an ethyl silicate. 18 The method of claim 15, characterized ized in that the acid catalyst is at least one acid chosen from the group comprising hydrochloric acid, nitric acid, acetic acid and sulfuric acid. 19 The method of claim 15, characterized ized in that the alcohol is a mixture of ethanol and isopropanol. A method according to claim 15, characterized ized in that the coating is deposited by de- spray pot, dip deposition or spray deposition rotation.